The present invention relates to a method for assembling and disassembling face mounted cutting inserts in multiple disc cutters.
Disc cutters with face mounted cutting inserts (also known as tangential, lay-down and edge-on mounted inserts) are known. In such a disc cutter, the cutting inserts are mounted in insert receiving pockets located at the peripheral portion of the cutter body. Each insert receiving pocket has a pocket base wall that faces axially. The pocket base wall is provided with a threaded bore that is substantially parallel to the axis of rotation of the cutter within the range of 0xc2x0 to 20xc2x0. Each cutting insert is mounted in an insert receiving pocket by means of a clamping screw that is directed substantially parallel to the axis of rotation of the cutter. The tightening or un-tightening of the clamping screw is done by means of an ordinary key, having an axis of rotation, in the form of a screwdriver or a xe2x80x9cTxe2x80x9d shaped key. Such a key has a head portion rotated with respect to an axis of rotation of the key and a holding portion connected to the head portion, spaced away therefrom and co-directionally therewith. Such a key engages the clamping screw and is directed so that its axis of rotation is substantially parallel to the axis of rotation of the cutter.
In some machining applications it is required to coaxially mount several disc cutters on a common shaft. Often, each cutter being axially displaced from an adjacent cutter a distance that is too small to enable the insertion of an ordinary key between two cutters in a direction such that the axis of rotation of the key is substantially parallel to the axis of rotation of the cutter. It is a common practice in the industry that, in order to initially mount cutting inserts in the face of the cutter, or to dismount worn cutting inserts and installing new ones, it is necessary to dismantle the disc cutters from the common shaft so that the insert receiving pockets are easily accessible. Such a dismantling of the cutters and re-assembling them on the common shaft is very time consuming. Furthermore, there is a need to re-adjust the cutters on the shaft each time they are re-assembled.
It is the object of the present invention to provide a method for assembling and disassembling face mounted cutting inserts in multiple disc cutters mounted on a common shaft without the necessity to dismantle the cutters from the shaft.
It is a further object of the present invention to provide a key for assembling and disassembling face mounted cutting inserts in multiple disc cutters.
In accordance with the present invention there is provided a method for assembling or disassembling cutting inserts, the method comprising the steps of:
(a) providing a rotary cutting tool assembly (20) comprising a plurality of coaxially mounted cutters (22) on a common shaft (24) having an axis of rotation (A), each cutter having a cutter body (26) in the general form of a circular disc, at least one of the plurality of cutters having a radius (R) and insert receiving pockets (30) in a peripheral portion (32) thereof, each of said insert receiving pockets having a threaded bore (38) substantially parallel to the axis of rotation (A), the at least one of the plurality of cutters being axially displaced from an adjacent cutter by a given distance (W),
(b) locating a cutting insert (28) having a through bore in each of the insert receiving pockets, the through bore being substantially parallel to the axis of rotation (A),
(c) securing each of the cutting inserts by means of a clamping screw (36) passing through the through bore and threadingly engaging the threaded bore (38), and
(d) tightening each clamping screw with a key (42), the key having a head portion (44), having a head axis (B), engaging the clamping screw and a holding portion (46) connected to the head portion and transversely directed to the head axis (B), the entire holding portion being distanced a first distance (D1) from the head axis (B), the first distance (D1) being at least 3 cm, the head portion being rotated with respect to the head axis (B), the head axis (B) being directed substantially parallel to the axis of rotation (A), in a view co-directional with the head axis (B) the entire holding portion having an angular extent (xcex1) of less than 90xc2x0 with respect to the head axis (B) and the entire holding portion being distanced a second distance (D2) from the axis of rotation (A), the second distance (D2) being greater than the radius (R) of the cutter.
Generally, the given distance (W) is less than 200 mm.
Typically, the given distance (W) is less than 50 mm.
In accordance with a first embodiment of the present invention, the key is xe2x80x9cLxe2x80x9d shaped having an integrally formed head portion, a front portion of the head portion constituting a driving portion and having a shape that mates with the shape of a screw head.
In accordance with a second embodiment of the present invention, the head portion of the key is provided with a ratchet (52).
In accordance with a third embodiment of the present invention, the key is provided with a torque measuring device (54).
In accordance with a fourth embodiment of the present invention, the key is provided with a swivel joint (56) located between the head portion and the holding portion.
In accordance with a fifth embodiment of the present invention, the key is provided with a resilient arm (58) that is connected between the head portion and the holding portion of the key, an open end (60) of the resilient arm is opposite the head portion of the key and spaced away therefrom.
In accordance with a sixth embodiment of the present invention, the key is provided with a pivotable double ended arm (62), a first end (66) of the arm is opposite the head portion of the key and spaced away therefrom and a second end (68) of the arm is opposite the holding portion of the key and spaced away therefrom.
In accordance with a seventh embodiment of the present invention, the head portion of the key is provided with a gear (72) and the key is operated by turning the holding portion around an axis (K) that is transverse to the head axis (B) of the key.
In accordance with a eighth embodiment of the present invention, the head portion (44) of the key is connected co-axially to a front end (77) of a flexible cable (74) retained within a body (82) of the key, a rear end (75) of the flexible cable is connected co-axially with the holding portion (46), the flexible cable being freely rotatable within the body (82) and the key is operated by turning the holding portion around an axis (K) that is transverse to the head axis (B) of the key.
In accordance with a ninth embodiment of the present invention, the head portion of the key is power operated.
If desired, the head portion of the key is detachably connected to the key.